Based on a case-control study completed several years ago in a local school district, we are continuing to investigate possible environmental risk factors for ADHD. In ongoing work, we are looking at maternal stress during pregnancy as a possible risk factor. (see Z01 ES49034; PI Dale Sandler, EB) In ongoing work on ALS, we are examining military and occupational exposures as risk factors for the diease and for their possible effects on survival after diagnosis. This work is in collaboration with researchers at Duke University and the Durham Veterans Administration Hospital using data from a case-control study of U.S. veterans. (see Z01 ES49005; LI Freya Kamel, EB) We have carried out a case-control study nested within the Agricultural Health Study to examine associations between Parkinson's disease and environmental risk factors, particularly certain pesticide exposures. We are also looking at selected candidate genes as susceptibility factors. This study employs data from the Agricultural Health Study as well as additional questionnaire data and field samples collected expressly for this effort. We have reported that the risk of Parkinson's disease associated with paraquat increases dramatically when the subject carries a homozygous deletion of the glutathione-S-transferase gene GSTT1 . We have observed that higher intake of N-3 polyunsaturated fatty acids was associated with lower risk of Parkinson's disease in general and appeared to lower the risk associated with paraquat use. Recently, we reported that polymorphisms in genes coding for peptidoglycan recognition proteins are associated with Parkinson's disease. We are also examining whether the use of personal protective equipment modifies the association between certain pesticides and Parkinson's disease. Analysis of data from this study is ongoing. (see Z01 ES44007 EB; LI Freya Kamel, EB) In other work, we have used data from the Atherosclerosis Risk in Communities Study to examine the role of plasma cholesterol and statin-use on the risk of Parkinson's disease. We concluded that higher levels of total cholesterol were associated with a lower risk whereas statin use was associated with a higher risk. We also used data from the NIH-AARP Diet and Health Study to look at potential associations between dietary fat intake and the risk of Parkinsons disease. Our results suggested that higher intake of N-6 polyunsaturated fatty acids is associated with a slightly higher risk of PD. (see Z01 ES101986 EB; PI Honglei Chen, EB) Data collection for a study of the effects of soy estrogen on neonatal development carried out at Childrens Hospital of Philadelphia is now complete. We are currently working with two commercial laboratories and the CDC to resolve some inter-laboratory differences in testosterone measurements. We have published a paper characterizing the performance of methods for cytological assessment of vaginal and urethral epithelium in infants. Ongoing analyses are directed a finding differences between soy-fed infants and breast-milk or cow-milk fed infants in the age trajectories of anatomical features that are likely influenced by estrogen. (see Z01 ES44006 EB; PI Walter Rogan, EB) A recently initiated effort will be using data from the Medical Birth Registry of Norway to estimate the gestational-age-specific risk of stillbirth among mothers with and without preeclampsia.